For people watching the Olympics, NBC and Microsoft tout the ability to view events on their own schedules, and follow niche sports that they might not see on television. The site, NBCOlympics.com, will be free to use, supported by advertising.

"One objective is to drive people to our broadcasts, but the other is to satisfy the interest and the appetite of the Olympic fan who simply can't get enough," said Gary Zenkel, the president of NBC Olympics, in an e-mail. Zenkel described it as "the most technically ambitious Internet project to date."